Electrolytic condenser



P 1934. R. D. MERSHON 1,974,579

ELECTROLYTIC CONDENSER Filed Nov. 27, 1929 3 Sheets-Sheet 1 F [6.1. PIC-5.2.

i ii

17 HI l n g t 17 1 1 i t 1 amoemtoz flbtommf W,MHSWW Sept. 25, 1934.

R. D. MERSHON 1,974,579

ELECTROLYTIC CONDENSER s Sheet-Sheet 2 Filed Nov. 27, 1929 WW H C aljvwto'c @31 M flue mega W,MWW

P 1934- R. D. MERSHON 1,974,579

ELECTROLYTIC CONDENSER Filed Nov. 27, 1929 3 Sheets-Sheet 5 FIGS.

FIG. 6.

21 san mm Patented Sept. 25, 1934 UNITED STATES ELECTROLYTIC CONDENSER Ralph D. Mersh on, New York, N. Y.

Application November 2 Claims.

This invention relates to electrolytic condensers of the type in which the anode or anodes are made of sheet metal, usually aluminum, wound to spiral form, preferably around a rod or stem, also of filming metal, to which the innermost spire or turn is electrically connected. The chief object of the invention is to provide an electrolytic condenser, and an anode therefor, in which the losses due to the resistance of the electrolyte to flow of condenser current is substantially lessened, without material increase in the-physical dimensions of the anode or material decrease of capacity.

Referring to the drawings,

Fig. 1 is a perspective view of a condenser anode as commonly made heretofore.

Fig. 2 is a perspective view of an anode embodying my present invention in one form thereof.

Fig. 3 is a cross sectional view of a condenser having an anode such as shown in Fig. 1, and also an anode of the improved type shown in Fig. 2.

Fig. 4 shows a strip of sheet metal attached to a rod or stem, ready for winding to the spiral form illustrated in Fig. 2.

Fig. 5 is a plan view of an embodiment in which the turns or spires of the anode are spaced and supported at top and bottom by attachment to radial arms and extending from a central stem.

Fig. 6 is a cross section on line 66 of Fig. 5.

Fig. 6a is a section on line 6a-6a of Fig. 6.

Fig. 7 is a plan view, and Fig. 8 a section on line 8-8 of Fig. 7, illustrating another embodiment, in which the spiresof the anode are attached to upper and lower rings.

The anode shown in Fig. 1 comprises a spirally wound sheet 10 of aluminum or other suitable filming metal, and a central rod or stem 11, also of filming metal, to which the innermost turn of the spiral is attached, the attachment being made preferably by inserting the end of the sheet into a slit in the rod and welding it there. Of course the sheet and rod are filmed. The rod usually serves as the anode terminal, and for this purpose the upper end may be threaded. Fig. 3 shows this anode as part of a condenser of a widely used type, in which the can 12, containing the electrolyte 13, is made of non-filming metal and serves as a cathode. When used in a filter network for by-passing the alternating component of rectified alternating current the anode 10 is connected to the positive side of the filter circuit and the cathode 12 is connected to the negative side. It will be observed that the condenser current flowing between the cathode, in the present instance the can 12, and the inner turns of the spiral anode, especially the middle portions 7, 1929, Serial No. 410,042

thereof, must pass through longer paths in the electrolyte than current from the outer turn or spire. To obviate this drawback I make the anode in axially spaced sections, electrically connected, preferably as in Fig. 2. The anode 15 there shown, also spiral in form, is made from the blank illustrated in Fig. 4, consisting of an elongated rectangular sheet of filming metal 16, having one or more longitudinal rows of apertures 17, which may be elongated and staggered, as indicated. One end of the sheet or strip is welded in slit 18 in the terminal rod or stem, around which the strip is then wound spirally. This produces the anode of Fig. 2, in which the openings 17, more or less in register, afford paths for the fiow of current from the inner spires directly to the cathode with, at most, but short travel axially of the anode.

Firm support of the anode spires is desirable, to prevent sagging, especially when the anode is made of very thin metal with numerous spires. The combined supporting rack and terminal shown in Figs. 5 and 6 is satisfactory for the purpose, and comprises a central stem or rod 20 of filming metal having upper and lower radial arms 21, 22, which may be welded in place, of the troughed or grooved form indicated in Fig. 6a and provided with spirally arranged recesses in which the upper and lower edges of the anode spires are welded inside of the grooves. The supporting arms are preferably in vertical alignment, as shown, and two sets of arms are desirable, but either set may be omitted, as will be readily understood, though in such case the unsupported edges may suffer distortion or radial displacement in handling. The innermost spire may be narrowed as indicated, for insertion in the slit 24 in stem 20, in which the inserted portion is welded.

Another form of combined support and terminal is shown in Figs. 7 and 8, comprising a plate 25 of filming metal, preferably annular in form, having an integral stem 26 to serve as a terminal. At two or more points the ring is formed with downward bends or depressed portions 27, having spirally arranged recesses in which the edges of the anode spires are welded. A similar support 28 may be provided for the bottom of the anode, to maintain uniform spacing of the spires. The annular form of the supports is particularly useful as permitting one anode to be placed or nested inside of another, as shown in Fig. 7, in which the inner anode is of the type illustrated in Fig. 5. If the two are to have the same efiective area the outer anode should have fewer spires or the inner anode should be longer, as will be readily understood.

In all the anodes illustrated the stem or rod, projecting above the spiral, may be used to support the anode, as for example in the manner in-= dicated in Fig. 3, in which the threaded stems 11 extend through openings in the insulating or non-conducting cover 30 and are secured to the latter by means of nuts 31. In a construction such as that shown in Figs. 7 and 8, in which the stem 26 is attached to the ring 25, the weight of the anode subjects the stem to stresses which may result in bending the stem. To obviate this possibility a plurality of stems may be provided, preferably arranged symmetrically or equiangularly around the axis of the anode. In Fig. 7 a second stem is indicated at 32, diametrically opposite the one shown at 26. The two may be used to suspend the anode in the manner illustrated in Fig. 3.

So far as their supporting and spacing functions are concerned, the stems 11, 20, 26 and 32, the arms 21 and 22, and the rings 25 and 28, may be made of hard rubber or other insulating material which possesses the necessary mechanical strength and will not harmfully contaminate the electrolyte. I prefer to make them of filming metal, however, as this gives each spire practically direct electrical connection with the anode terminal. This is especially advantageous when the number of spires is large. If the stems are nonconducting, or if, when of filming metal, they are not electrically connected to the spirals, any suitable means may be provided for connecting the spirals with the external circuit, as will be readily understood. Welding is the most satisfactory method of making electrical connection between anode parts which are to be submerged in the electrolyte, but good mechanical connection may sometimes be employed. If made of suitable non-filming metal any of the devices shown may serve as a cathode.

It is to be understood that the invention is not limited to the constructions herein specifically described but can be embodied in other forms without departure from its spirit.

I claim 1. In an electrolytic condenser, an electrode of the spiral type made in electrically connected sections mounted on a rod disposed axially at the spiral origin of the sections, the said sections being spaced apart axially so that when immersed in an electrolyte currents from inner spires will have short paths through the electrolyte to the outside of the electrode.

2. In an electrolytic condenser, a spirally wound electrode made of a sheet of metal having a longitudinal series of apertures serving to divide the electrode into axially spaced electrically connected sections, whereby currents from inner turns or spires, when the electrode is immersed in an electrolyte, have short paths through the electrolyte to the outside of the electrode.

3. In an electrolytic condenser, an electrode of spiral type having a spiral series of circumferentially elongated apertures dividing the spiral into electrically connected axially spaced sections.

4. In an electrolytic condenser, an electrode of the spirally wound type, comprising a plurality of axially spaced sections electrically connected by narrow, axially extending strips integral with the spires or turns which they connect.

5. In an electrolytic condenser, an electrode of the spiral type, comprising an elongated strip of sheet metal having a plurality of longitudinal rows of longitudinally elongated closely spaced apertures, the strip being wound to spiral form with the rows of apertures running spirally.

6. In an electrolytic condenser, an electrode of the spiral type made in sections having a plurality of the spires thereof directly connected with the corresponding spires of adjacent sections, said sections being spaced apart axially so that when immersed in an electrolyte currents from inner spires will have short paths through the electrolyte to the outside of the electrode.

7. In an electrolytic condenser, an electrode of the spiral type made in electrically connected sections mounted on a rod disposed axially at the spiral origin of the sections, the said sections being spaced apart axially so that when immersed in an electrolyte currents from inner spires will have short paths through the electrolyte to 'the outside of the electrode, and the electrode being provided with one or more radially extending members attached to its spires or turns and adapted to support the said spires or turns against axial displacement.

8. An electrolytic condenser comprising a metallic can constituting a cathode, an electrolyte in said container, and a filming anode consisting of a compact curved plate having active inner and outer surfaces and having portions of its surface defining narrow paths of high resistance from inner surface portions of the anode through the electrolyte to the cathode can, the anode having perforations to permit direct substantially radial conduction from-inner surface portions of the anode through the electrolyte to the cathode can.

9. In an electrolytic condenser, an anode comprising a spiral aluminum sheet having radially spaced convolutions and having a spiral series of circumferentially elongated apertures dividing the spiral into electrically connected axially spaced sections.

10. An electrolytic filter condenser for by-pass- 1 ing the alternating component of rectified alternating current and comprising in combination, a metallic can constituting a cathode for connection to the negative side of a filter circuit, an electrolyte in said container, and a filming anode for connection to the positive side of a filter circuit and consisting of a compact curved plate having active inner and outer surfaces and having portions of its surface defining long paths of high resistance from inner surface portions of the anode through the electrolyte to the cathode can, the anode having perforations to permit direct substantially radial conduction from inner surface portions of the anode through the electrolyte to the cathode can.

RALPH D. MERSHON. 

